In a conventional ABS actuator, a fluid passage formed in a housing is opened and closed by a solenoid valve. Further, a coil portion of a solenoid valve is sandwiched between the housing and the cover, and the coil portion is pressed to a cover by an elastic member disposed between the coil portion and the housing (for example, as disclosed in Japanese Patent Laid-Open Application No. 11-43031) so as to avoid looseness of the coil portion.
However, force for pressing the coil portion to the cover is reaction force generated by compressive deformation of the elastic member, and the reaction force largely varies in accordance with an amount of deformation. Further, when a dimensional variation of a component part is taken into consideration, the amount of deformation of the elastic member also greatly varies, and thus it is necessary to assume that very large reaction force is applied in terms of a design. Therefore, it becomes necessary to increase rigidity of the coil portion and the cover so as not to deform or destroy them, or it is necessary to increase strength by using a larger screw for connecting the cover with the housing. This caused increase in the cost and the size of the ABS actuator.